199 results about "Carbohydrate Linkage" patented technology

The invention relates to the technical field of plant polysaccharide extraction, in particular to a process for synergistically extracting rape pollen polysaccharide by a compound enzyme, which comprises the following steps: crushing rape pollen to 200-300 meshes by pulse airflow, performing microwave-ultrasonic degreasing by using a 85% ethanol solution, mixing with an acetic acid-sodium acetate buffer solution with the pH value of 4.8, and performing ultrasonic extraction to obtain a crude extract; the method comprises the following steps: adding a compound enzyme system which is immobilized by Fe3O4 (at) SiO2 nanoparticles by cellulase, pectinase, protease and beta-glucosidase according to a mass ratio of 2: 1: 1: 0.5, carrying out enzymolysis for 4 hours in a 50 DEG C constant-temperature water bath and a 15V / cm pulsed electric field, carrying out enzyme deactivation on enzymatic hydrolysate, carrying out gradient ethanol precipitation, carrying out ultrafiltration deproteinization, and carrying out vacuum pulsation freeze drying to obtain the polysaccharide. According to the method disclosed by the invention, the cell wall breakage rate and the enzymolysis efficiency are improved through pulsed airflow crushing, magnetic nano immobilized enzyme and pulsed electric field assistance, the polysaccharide yield reaches 7.32%, the purity is 91%, the beta-glucosidic bond proportion and the antioxidant activity are remarkably improved, the enzyme can be recycled and reused, the drying time is shortened, and efficient and low-consumption extraction is realized.

The invention relates to a preparation method of high-substitution-degree cationic micro-nano cellulose and application of the high-substitution-degree cationic micro-nano cellulose to improvement of water filtering performance of paper. In the enzymolysis pretreatment process, beta-1, 4 glucosidic bonds among glucose molecules are cut off, and more reaction binding sites are created for cationization after cellulose in an amorphous region and a part of crystalline region is hydrolyzed, so that the use amount of chemical reagents can be effectively reduced, and the environmental pollution is reduced. The prepared high-substitution-degree cationic micro-nano cellulose (CMFC) has abundant positive charges, weakens the hydrogen-bond interaction of cellulose molecules, improves the content of nano-fibrillation, and effectively reduces the mechanical preparation energy consumption of the CMFC. CMFC pulp is added into paper pulp fibers, so that pores of the paper fibers are blocked, more filler is intercepted, and the filler is difficult to be completely brought into white water by water flow in the water filtering process, so that the retention rate is increased, and the water filtering performance is effectively improved.

The invention discloses a method for improving moso bamboo cellulase hydrolysis conversion efficiency through amino acid-based deep eutectic solvent pretreatment, and belongs to the technical field of biomass recycling. The method comprises the following steps: mixing an L-cysteine solid and a formic acid solution, performing water bath heating to prepare an acidic eutectic solvent, performing microwave-assisted eutectic solvent pretreatment on moso bamboos, and performing filtration separation and enzymolysis; wherein the molar ratio of the L-cysteine to the formic acid is 1: (4-5). A deep eutectic solvent formed by formic acid and cysteine has a strong hydrogen bond network and an acid environment, beta-O-4 ether bonds in lignin are promoted to be broken, sulfydryl of cysteine participates in nucleophilic attack, a lignin-carbohydrate complex is further destroyed, formic acid can hydrolyze acetyl and glucosidic bonds in hemicellulose, and the lignin-carbohydrate complex is further destroyed. And degrading into an oligomer or monosaccharide. The phyllostachys pubescens components are efficiently separated, the cellulose enzymolysis saccharification capacity is improved, and effective utilization of all the phyllostachys pubescens components is facilitated.

The invention discloses hyaluronic acid endo-lyase and application thereof in preparation of hyaluronic acid with specific molecular weight. The hyaluronate lyase can cut a beta1-4 glucosidic bond to generate unsaturated oligosaccharide, has the characteristics of high enzyme activity and catalytic efficiency and good stability, and the enzymolysis reaction can be carried out in water without adding metal ions and a buffer solution, so that the hyaluronate lyase has the advantages of simplicity in product recovery and no need of removing salt. The hyaluronate lyase not only can be used for degrading hyaluronic acid, but also can be used for degrading chondroitin sulfate, not only can be used for preparing polysaccharide with specific molecular weight, but also can be used for completely degrading the polysaccharide into unsaturated disaccharide, and has a wide application prospect in the fields of cosmetics, food, health care products, medicines and the like.

The invention belongs to the technical field of chitosan oligosaccharide preparation, and particularly relates to a method for preparing chitosan oligosaccharide based on compound enzyme. According to the method for preparing the chitosan oligosaccharide based on the compound enzyme, a multi-enzyme synergistic system is matched with the design of a specific protective agent, chitosanase and chitinase can cooperatively cut beta-1, 4 glycosidic bonds of chitosan and control molecular weight distribution of products, meanwhile, chitinase can directionally cut the beta-1, 4 bonds at the tail end of chitosan, and the molecular weight distribution of the products is controlled. The papain is used for removing protein impurities in the chitosan to realize accurate control of the polymerization degree. Besides, a specific protective agent matched with the multi-enzyme synergistic system is specifically designed, the specific protective agent and the multi-enzyme composition act together, the molecular weight distribution width can be remarkably reduced, the yield and the DP 4-8 proportion can be increased, meanwhile, physical field ultrasonic assistance is added in the enzymolysis treatment process, and the enzymolysis treatment efficiency is improved. The combination of the substrate and the enzyme is further promoted, and the reaction time is shortened.

The invention discloses purified barley seedling polysaccharide as well as a preparation method and application thereof. The polysaccharide is prepared from six monosaccharides, namely rhamnose, galacturonic acid, glucose, galactose, xylose and arabinose in a molar ratio of 2.88: 3.39: 1.51: 1: 0.76: 3.2. The relative molecular weight is 254.09 kDa. A fermentation method is combined with an innovative purification process, so that the barley seedling polysaccharide monomer with high purity and uniform structure is obtained for the first time. Through a multi-dimensional characterization technology, fine structure characteristics such as monosaccharide composition, glucosidic bond connection mode and branching degree are systematically analyzed, and a reliable material basis is provided for establishing structure-function accurate association. The purified barley seedling polysaccharide has a remarkable effect of promoting intestinal peristalsis, not only lays a scientific foundation for deep processing of barley seedlings and research and development of related functional products, but also provides a new theoretical support for relieving intestinal peristalsis disorder, and has a wide application prospect.

To provide a technique capable of effectively recycling each recovered material as a single material by selectively decomposing, separating and recovering a fiber having a β - glycoside bond from a mixed fiber comprising the fiber having the β - glycoside bond such as cotton and other fibers such as polyester by a simple treatment in a short time under a non-pressurized condition.SOLUTION: A treatment method comprising selectively decomposing a fiber having a β - glycosidic bond from a mixed fiber containing the fiber having a β - glycosidic bond and a fiber composed of another material by a treatment using a deep eutectic solvent (DES) formed by mixing a hydrogen bond donor with a hydrogen bond acceptor at a molar ratio of 0.50 or more and 6.00 or less, and recovering the fiber composed of another material in a fibrous form.SELECTED DRAWING: None

The invention relates to the technical field of skin care products, in particular to a glucan product as well as a preparation method and application thereof. According to the invention, the glucan product is obtained by performing enzymolysis on the material containing the glucan through the incision enzyme for specifically treating the 1, 4 glucosidic bonds, and the number ratio of the 1, 4 glucosidic bonds to the 1, 3 glucosidic bonds in the glucan product is 1.8 or less, so that the intramolecular and intermolecular agglomeration of the glucan is improved, the room-temperature stability of the glucan is improved, and the yield of the glucan is increased. And the obtained glucan product can be added in cosmetics in a large amount, has a stronger anti-inflammatory effect, and has an outstanding effect of promoting skin soothing after being added into the cosmetics.

The present disclosure relates to poly alpha-1,6-glucan ether compounds comprising poly alpha-1,6-glucan substituted with at least one positively charged organic group and having a degree of substitution of about 0.001 to about 3.0. The poly alpha-1,6-glucan comprises a backbone of glucose monomer units, wherein greater than or equal to 40% of the glucose monomer units are linked via alpha-1,6 glycosidic bonds, and optionally about 3% of the backbone glucose monomer units have branches via alpha-1,2 and / or alpha-1,3 glycosidic bonds. Compositions comprising poly alpha-1,6-glucan ether compounds can be used in various applications.

The invention discloses high-purity resistant dextrin and a preparation method thereof, and the preparation method comprises the following steps: (1) adding 4, 3-alpha-glucosyltransferase into a maltodextrin aqueous solution or a starch solution treated by starch debranching enzyme to react, and after the reaction is finished, deactivating the enzyme; (2) adding alpha-amylase into a reactant in the step (1) to react, and deactivating the enzyme after the reaction is finished; (3) adding alpha-glucosidase into the reactant in the step (2) for reaction, and deactivating the enzyme after the reaction is finished; (4) adding saccharifying enzyme into the reactant in the step (3) to react, and deactivating the enzyme after the reaction is finished; and (5) adding yeast powder into the reactant in the step (4) for fermentation, filtering by a filter membrane after fermentation, collecting membrane filtrate, and drying to obtain the high-purity resistant dextrin. The preparation process is simple and efficient, the product purity is high, the proportion of alpha-1, 3 glucosidic bonds in the prepared resistant dextrin is 40% or above, and the purity of the resistant dextrin is 80-90%.

This invention discloses a method for determining the content of suberin monomers in the suberized tissue of yam tubers. Suberin is a macromolecular polyester, with monomers mainly covalently linked by oxygen-ester bonds. Its aliphatic compounds are linked to the polysaccharide components in the cell wall by glycosidic bonds and located on the inner side of the cell wall. Therefore, to determine the suberin monomer content, it is necessary to first destroy the plant cell structure, and then hydrolyze the oxygen-ester bonds between the suberin monomers to release the suberin monomer components. This invention first uses ultrasonic pretreatment to destroy plant cells, and then uses lipase hydrolysis combined with ultrasonic assistance and acid hydrolysis (sulfuric acid / methanol) to fully and efficiently hydrolyze the suberin into monomers. The reagents used are relatively safe and non-toxic, and the operation is relatively simple, solving the technical problem of difficult determination of suberin monomer content in the study of suberin metabolism after yam tuber injury healing.

The application discloses a method for controllably degrading glycosidic bonds of hyaluronic acid by programmed temperature rising. The method is used for high-molecular-weight hyaluronic acid aqueous solution, and a combination of an oxygen oxidant and an acidic additive is used to controllably cut and degrade glycosidic bonds in the macromolecule through a heating process of programmed temperature rising control system, so as to obtain oligomeric hyaluronic acid. The oligomeric hyaluronic acid prepared by the method has very good stability and no color change after long-time storage. The oligomeric hyaluronic acid prepared by the method can be applied to the fields of cosmetics, food, medicine and the like, and has very strong practical value.

The invention discloses a flavor modifier, atomized essence and an aerosol generating device, and relates to the technical field of essence. According to the technical scheme, the flavor modifier comprises an active agent, a compound containing a phenolic hydroxyl group and-O-beta-D-glucosidic bond or a compound containing an alcoholic hydroxyl group and-O-beta-D-glucosidic bond is selected as the active agent, and the flavor modifier can be weakly combined with a Piezo channel in a trigeminal nerve to directly modulate a trigeminal nerve mechanoreceptor, so that the flavor of the trigeminal nerve is improved. The activity of the Piezo channel is inhibited, so that the sensitivity of the Piezo channel to mechanical friction of aerosol particles is reduced, and the nasal cavity roughness is reduced. Meanwhile, the flavor modifier disclosed by the invention can also cooperate with olfactory signals transmitted by other components in the atomized essence to jointly improve the smoothness, the fineness and the overall moist feeling of the fragrance.

The present application relates to starch production technical field, especially disclose a kind of green preparation method for modified starch for replacing hydroxypropyl distarch phosphate.The green preparation method, cassava starch is used as raw material, specifically includes the following steps: (1) cassava starch is mixed with water uniformly, and starch suspension is prepared;(2) adding alpha-amylase to starch suspension for glycosidic bond enzymolysis, then passivate enzyme activity;(3) the enzymatic hydrolysate is used to hexose oxidase and oligomeric glucan is subjected to lactonization reaction, then passivate enzyme activity;(4) the final enzymatic hydrolysate is centrifuged, washed with water, the precipitate is freeze-dried, and enzyme modified cassava starch is obtained.The paste viscosity, freeze-thaw stability, shear resistance, anti-aging and other chemical properties of the enzyme modified cassava starch prepared by the present application are close to or better than hydroxypropyl distarch phosphate, and the preparation process is simple, short cycle, green and safe, low in production cost, simple in equipment, suitable for industrial production, and safe and pollution-free during production.

The invention provides a method for identifying a connection position of a glucosidic bond in an oligosaccharide glucosidic bond isomer, and belongs to the technical field of analysis and detection of saccharide isomers. According to the method for identifying the connection position of the glucosidic bond in the oligosaccharide glucosidic bond isomer, oligosaccharide compounds in a to-be-detected sample are separated at the same time on the basis of a derivatization reagent with a structure as shown in a formula I by utilizing a high performance liquid chromatography-tandem mass spectrometry technology; structural specificity diagnosis ions are generated based on an electron collision excitation collision mode of organic matter ions to identify the types of glycosidic bonds of disaccharide, trisaccharide, tetrasaccharide, pentasaccharide, hexasaccharide and heptasaccharide isomers of different glycosidic bonds. The method is high in identification efficiency and accurate in identification, and can meet the requirements of glycogen storage disease diagnosis biomarker research. And the formula I of the # imgabs0 # is shown in the specification.

The invention discloses a compound microorganism fermented attenuated aroma-enhanced potato residue feed and a preparation method thereof, and belongs to the field of feed processing. The feed comprises potato residues, crop straw particles, corn flour, bran, soybean meal, urea, ammonium sulfate and a compound microbial agent, wherein the compound microbial agent comprises bacillus velezensis and lactobacillus plantarum. The preparation method comprises raw material pretreatment; preparing a microbial agent; performing mixed fermentation; and post-processing. The bacillus velezensis secretes glycosidase, and glucosidic bonds of the glycoalkaloid are subjected to enzymolysis; lactobacillus plantarum is metabolized to generate lactic acid to create an acidic environment to promote chemical degradation of glycoalkaloid, and the double bacteria cooperate to inhibit growth of mould, so that efficient attenuation is realized. The bacillus velezensis metabolizes to generate glucose, ethanol and free amino acid, and the lactobacillus plantarum metabolizes to generate ester flavor substances, so that the feed is endowed with strong fermentation aroma. Meanwhile, the pungent smell of volatile aldehyde substances is eliminated through double-bacterium synergism.

The invention provides emblic leafflower fruit polysaccharide with a weight losing effect and an efficient preparation method and application thereof, and belongs to the field of plant polysaccharide. The preparation method comprises the following steps: performing powdering, water extraction and concentration on a phyllanthus emblica raw material, adding an alcohol solvent for precipitation, and drying to obtain phyllanthus emblica crude polysaccharide; after the phyllanthus emblica crude polysaccharide is dissolved, impurities are removed through membrane filtration, protein substances are adsorbed through a reversed-phase chromatographic column, flow-through liquid and water leacheate are collected and combined, small-molecular-weight substances are removed through a membrane bag, intercepted liquid is collected and dried, and the phyllanthus emblica polysaccharide is obtained. The phyllanthus emblica polysaccharide has alpha-type and beta-type glycosidic bonds, and has linear polysaccharide chains and aggregates formed by a plurality of chains. The emblic leafflower fruit polysaccharide is used for preparing products for reducing fat and blood sugar, and can also be used for preparing medicines for preventing and treating abnormal glucose metabolism, abnormal lipid metabolism, related diseases, obesity and liver injury caused by obesity. The phyllanthus emblica polysaccharide extraction and purification preparation method is simple and efficient, and is convenient for industrial implementation.

This invention discloses a pullulanase mutant with enhanced catalytic activity against highly branched dextrin substrates, its construction method, and its applications, belonging to the fields of enzyme engineering and biotechnology. This invention obtains two mutants, D139A and D139E, by site-directed mutagenesis of the pullulanase derived from Klebsiella pneumoniae at position 139 aspartic acid residue. Compared with the wild-type enzyme, both mutants maintain high hydrolytic activity against pullulan polysaccharides while significantly improving hydrolytic activity against dextrin substrates with high α-1,6 glycosidic bond content. Specifically, the hydrolytic activity against dextrin substrates with 6% and 10% α-1,6 bond content is increased by up to 242% and 110%, respectively. The pullulanase mutants obtained in this invention exhibit excellent catalytic performance in the enzymatic debranching reaction of highly branched dextrin substrates, showing promising application prospects in starch deep processing and related biomanufacturing fields.

The present invention relates to use of an enzyme that cleaves both alpha- and beta-1,4-glycosidic bonds and, more particularly, the present invention provides α-L-fucosidase which has α-1,4-glucosidase and β-1,4-galactosidase activities and thus is capable of producing glucose and / or galactose, which are monosaccharides, from non-fucosylated saccharides. The enzyme has transglycosylation activity and thus produces maltooligosaccharides having a higher degree of polymerization than maltooligosaccharides used as a substrate, thereby being applicable to the development of high-value-added new materials in the food industry.

The invention belongs to the technical field of plant polysaccharide, and particularly discloses caulis spatholobi polysaccharide, a preparation method thereof and application of the caulis spatholobi polysaccharide in preparation of medicines for treating inflammation. Monosaccharide in the caulis spatholobi polysaccharide disclosed by the invention comprises mannose, glucuronic acid, galacturonic acid, glucose and arabinose in a molar ratio of (0.5-0.6): (0.3-0.5): (1-2): (1-2): (0.5-1.5). The caulis spatholobi polysaccharide provided by the invention is a novel uniform-structure polysaccharide which is separated from caulis spatholobi rattan for the first time, has a slightly acidic pH value, definite monosaccharide composition, definite molecular weight and clear glycosidic bond linking mode, has an anti-inflammatory effect, and is expected to be developed into a new anti-inflammatory drug. The preparation process is mild in condition, simple to operate and environment-friendly.

The invention belongs to the field of biological medicine, particularly relates to a preparation method of chondroitin with controllable molecular weight, and particularly discloses chondroitin which takes an initiator as an initial polymerization substrate, n comonomers are sequentially bonded to the non-reducing tail end of the initiator, the comonomer is formed by acetylated hexosamine and uronic acid through a glucosidic bond; the comonomer and an initiator are polymerized under the catalysis of polymerase to form polysaccharide with a certain molecular weight, namely the chondroitin disclosed by the invention. The chondroitin preparation technology disclosed by the invention can be used for preparing chondroitin with linear change of molecular weight, wide controllable molecular weight range and narrow molecular weight distribution, and the molecular weight range can be 1-5 million; the chondroitin prepared by the technology has the advantages of convenience in operation, high efficiency, reliability and the like, and the chondroitin prepared by the technology can be used for preparing the chondroitin. The chondroitin can be used for preparing the chondroitin from the chondroitin prepared by the technology by the aid of the preparation technology of the chondroitin, and the chondroitin can be used for preparing the chondroitin with the preparation technology.

The application relates to a preparation method of a mushroom extract, which comprises the following steps: placing pretreated mycelium in subcritical water as an extraction system to perform extraction, maintaining countercurrent circulation during the extraction, the flow rate being 3 mL / (min.g mycelium), and obtaining a crude product; purifying the crude product to obtain a mushroom extract; wherein the subcritical water extraction process controls extraction conditions in stages according to the following procedure: first stage: the pressure is 4 MPa, the temperature is 115 DEG C, and the holding time is 5 min; second stage: the pressure is increased to 8 MPa, the temperature is increased to 125 DEG C, and the holding time is 3 min; third stage: the pressure is decreased to 6 MPa, the temperature is adjusted back to 110 DEG C, and the holding time is 2 min. The preparation method of the application controls the pressure and temperature parameters of subcritical water in stages, combines countercurrent circulation, improves the extraction efficiency of beta-glucan, and inhibits glycosidic bond hydrolysis through a dynamic pressure gradient to protect the main chain structure integrity of polysaccharide.

The invention discloses polysaccharide capable of improving symptoms of alcoholic liver diseases as well as a preparation method and application of the polysaccharide, and belongs to the technical field of biological medicines. The polysaccharide capable of improving the symptoms of the alcoholic liver disease is extracted and purified from yellow water, the molecular weight of the polysaccharide is 12 kDa to 16 kDa, the polysaccharide is formed by connecting glucose units through glucosidic bonds, and the main chain glucosidic bond connection mode is [-> 4-alpha-Glcp-1-> 4-alpha-Glcp-1-> 4-alpha-Glcp-1-> 4-alpha-Glcp-1->]. The polysaccharide provided by the invention shows a clear and powerful effect of improving the alcoholic liver disease on an animal model, is derived from a natural product, is small in expected toxic and side effects, high in safety, simple in preparation method, relatively low in cost and easy to realize large-scale production, and provides a new way for preventing and treating the alcoholic liver disease.

The present application belongs to the technical field of application of fungal polysaccharides, and particularly relates to a Boletus edulis fruiting body polysaccharide as well as a preparation method and application thereof. Polysaccharides in Boletus edulis fruiting bodies are extracted, and the chemical structure of BDP-F is characterized by ultraviolet-visible light, Fourier transform infrared spectroscopy, one-dimensional nuclear magnetic resonance and two-dimensional nuclear magnetic resonance. The research results show that BDP-F is mainly composed of mannose, glucose, galactose and fucose. Methylation and nuclear magnetic resonance analysis show that the glycosidic bond of BDP-F is (1→6)-alpha-d-galactose, the main chain is composed of ->6)-alpha-d-galp-(1→ residues, and the O-2 position is branched by alpha-L-Fucp-(1→ and alpha-D-Manp-(1→ residues. Through DPPH free radical, hydroxyl radical and superoxide anion radical scavenging experiments, it is shown that BDP-F has the ability to serve as a natural antioxidant, and BDP-F can also reduce alcohol-induced GES-1 cell damage through antioxidant and anti-inflammatory effects within the experimental concentration range.

The invention belongs to the technical field of natural product extraction and preparation, and particularly relates to a method for ultrasonic compound enzyme assisted extraction of North America crabapple polysaccharide. According to the method, North America crabapple is taken as a raw material, and the North America crabapple polysaccharide is extracted and prepared by optimizing process conditions of an ultrasonic compound enzyme-assisted extraction method by utilizing a response surface method. Compared with a conventional hot water extraction method, the polysaccharide extraction rate is remarkably improved. An infrared spectrum and a scanning electron microscope are used for determining the structure of the malus prunifolia fruit polysaccharide, and the result shows that the malus prunifolia fruit polysaccharide contains a pyranoid ring, a beta-glucosidic bond and an alpha-glucosidic bond which are related to various biological metabolism. And finally, determining superoxide anion removal capacity and cholesterol adsorption capacity of the North American malus prunifolia fruit polysaccharide to find that the North American malus prunifolia fruit polysaccharide has good antioxidant activity and blood fat reducing activity. Therefore, the North America plum-leaf crab polysaccharide can be widely applied to the fields of functional foods, nutritional supplements, natural plant antioxidants and the like in the future, so that the comprehensive utilization value of the North America plum-leaf crab is effectively improved.

The invention relates to a novel chemical cross-linking agent with mass spectrum fragmentable trehalose disaccharide as a skeleton structure and a preparation method thereof. The cross-linking agent disclosed by the invention has the following characteristics: 1) trehalose disaccharide is used as a skeleton structure, so that the cross-linking agent has excellent biocompatibility; 2) the trehalose skeleton has a pair of symmetrical mass spectrum fragmentable glucosidic bonds, so that a cross-linked peptide fragment can be simplified into a conventional peptide fragment modified by a cross-linking agent fragment; 3) the enrichment of the cross-linked peptide fragment can be realized by the trehalose skeleton under the condition of not adding an enrichment handle; and 4) active groups of the cross-linking agent comprise but not limited to a plurality of reactive groups such as succinamide ester, diaziridine, phenylsulfonyl fluoride, hydrazide group, amino group, hydroxylamine group and the like, and chemical cross-linking of a plurality of amino acids except lysine is realized. The trehalose cross-linking agent disclosed by the invention is applied to the field of proteomics, and provides technical support for realizing large-scale analysis of a protein complex in a complex sample, spatial structure analysis of protein and a protein-protein interaction network.

A type based on 3 O A method for stereoselectively synthesizing α-oxyglycosides using a quinaldine ester glycan donor, comprising the steps of: using 3- O Quinaldine ester glucalose is a sugar donor, a catalyst, a ligand, triethylamine and a sugar acceptor and an organic solvent are added, and the reaction is stirred at 100-120 ° C. The reaction progress is monitored by TLC. After the reaction is carried out for 20-24 hours, the reaction is terminated to obtain an α-2,3-unsaturated oxygen glycoside. The technical solution of the present invention preferentially generates a product with a β configuration during the glycosidation reaction. Under the action of high temperature and palladium catalyst, the original β-glycosidic bond is broken and regenerated with an α configuration to obtain a thermodynamically stable α-2,3-unsaturated oxygen glycoside. The method has a wide range of substrate applicability, and the stereoselectivity of most substrates can reach at least α:β=10:1.

The application discloses a preparation method of codlane oligosaccharide, and comprises the following steps: mixing codlane polysaccharide with L molecular sieve, ball-milling and grinding, adding a solvent to dissolve, separating the L molecular sieve from the solid-liquid, and drying to obtain the codlane oligosaccharide; the L molecular sieve has a chemical composition of 1-5K2O*1.0Al2O3*5-10SiO2*1-5H2O and has straight pores; the L molecular sieve with the straight pores can selectively cut the glycosidic bond of the codlane to prepare the codlane oligosaccharide; thus, the codlane oligosaccharide can be efficiently prepared, and the L molecular sieve can be repeatedly used; the method does not need a large amount of water or other solvents to participate in the reaction, has the advantages of environmental friendliness and low cost, and has obvious advantages compared with the prior art, and is more beneficial to industrialization.

The invention relates to the technical field of carbohydrate informatics, in particular to a carbohydrate biomacromolecule property prediction method and system based on a graph neural network and chemical fingerprints. Comprising the following steps: modeling a carbohydrate chain sequence into an undirected graph, regarding monosaccharide and glucosidic bonds as nodes in the graph, introducing a virtual node for storing fingerprint features, extracting molecular fingerprint information from the sequence, constructing two different adjacent matrixes Afull and Aori with virtual node connection and without virtual node connection, and constructing two adjacent matrixes Afree and Aori; the dimension of the fingerprint features is reduced to be consistent with the node features, the features are replaced with molecular fingerprint features by positioning the positions of virtual nodes in the graph, the first three layers transmit Aori to enable a model to learn topological structure information of the graph, and the last layer transmits Afull to achieve fusion of the graph structure and the fingerprints. And pooling and splicing node features obtained after convolution of each layer to obtain final sugar chain representation for predicting different properties of sugar chains. According to the method, the graph structure and chemical fingerprint information of the sugar chain can be effectively combined to obtain more meaningful sugar chain representation.

This invention provides an extract of *Hedyotis diffusa*, its preparation method, and its uses. When the extract is measured under reversed-phase high-performance liquid chromatography, the peak area A of 6''-malonyl *Hedyotis diffusa* I is... M Peak area A with cypermethrin I B The ratio is less than 0.1, and the peak area A of free kaempferol is... K With A B The ratio shall not exceed 0.15. The preparation method includes: adjusting the pH of the aqueous extract of *Kaempferia galanga* to 11-13.5, and performing alkaline hydrolysis at 25-65°C for 20-60 minutes. This invention utilizes the difference in stability of malonyl bonds and glycosidic bonds under alkaline conditions to achieve the selective conversion of 6''-malonylkaempferol I to kaempferol I, increasing the content of kaempferol I while maintaining the integrity of the glycosidic bonds and inhibiting or controlling the formation of free kaempferol. The resulting extract can be used to prepare anti-inflammatory and antioxidant drugs or health foods.